Monthly Archives: June 2012

Bud Markhart

Tuesday morning I started the day by going outside, lighting a propane torch, and doing a little bit of flame – weeding for a demonstration.  Then I went inside, answered a few e-mails, and worked on a paper.  Around 4:00 I decided to go get a haircut because Wednesday I was due to speak before a portion of the Minnesota congress, along with a Professor in the department of Plant Pathology, to seek funding for a project that we have which identifies Dutch elm disease resistant elms in Minnesota.

In short, up until about 4:00 on Tuesday, I was feeling pretty darn professorial not to mention highly important.

Then, just before I headed out the door, an e-mail came across my computer screen, letting our department know that Bud Markhart had passed away.

For those of you who didn’t know Bud, he was a professor in the Department of Horticultural Science here at the University of Minnesota.  He was a plant physiologist who also did a lot of lecturing and work with organics.  He taught, among other things, a hands-on organic production course.

His passing wasn’t a surprise.  He was only 60, but he’d been fighting cancer for a few years and all of us in the department were aware that he probably didn’t have much time left.  Still, it hurts to lose someone like him.

As I’ve gone through my academic career I’ve had the opportunity to meet a lot of academics.  To make an unfair generalization, we tend to be self-righteous, self-important, and highly critical of others.  Bud was none of these things, and because of that he was loved and respected by many people both inside and outside of academia, but especially by students who were deeply appreciative of a professor who treated them as equals and didn’t talk down to them.  He earned the highest teaching award presented by the University of Minnesota, the Morse Alumni Teaching Award, a couple of years ago.  But the fact that he taught a class this past spring despite his illness reveals more about his commitment to students than any award could.

Personally, well, this is the guy who invited my wife and I to his house for Thanksgiving the first year that I lived in Minnesota.  In fact, he’s the guy who invited my Dad and me over my first day in Minnesota.

I think that a lot of people who talk about the recently departed refer to themselves as being closer to the departed than they actually were, and I don’t want to do that.  Bud and I were colleagues and, though I considered Bud a friend, we weren’t particularly close.  Still, I always knew that Bud’s door was open if I ever wanted to talk about anything.  He cared about people and he let it show.  His presence in our department, and in the small world that is horticulture, will be sorely missed.

MossTiles – a really bad idea

A few months ago a colleague alerted me to MossTiles, which can be attached to walls to create interior vertical gardens. They look really cool, and I assumed they consisted of some tough little moss species rooted in a mesh-enclosed planting mix. But the more I read about them, the more confused I became. They don’t need light – or fertilizer – or water (though misting them occasionally is recommended). More investigation was in order.

It turns out that these aren’t made from moss at all, but lichens – specifically reindeer moss (Cladonia rangiferina). This slow-growing lichen is harvested in Scandinavia, "stabilized" in a salt solution, glued onto tiles with a resin, then dyed one of twelve different colors.

Come on. This isn’t a plant anymore. It might as well be made out of plastic. All the misting does is keeping them from drying out and crumbling to pieces.

Even worse, reindeer moss is a major food source for caribou and other large ruminants. It’s so slow growing that it’s a threatened (and protected) species in some parts of the world. Do we really need to have preserved plants hanging on our walls like some kind of botanical trophy?

If so, be sure you’ve got a fat wallet. Installation of MossTiles costs about $200 per tile.

Grow Something Rude and Smelly!

Tired of
Tradescantia? Sick of Stachys? Exhausted from Echinacea?
Stick THIS in your border!



Dracunculus vulgaris
  at the Hahn Horticulture Garden, Virginia Tech. Hardy to USDA Zone 5b.

Closely related (as one might imagine) to
Amorphophallus. Lovely silver-splashed foliage, velvety crimson spathe, and big honkin’ spadix in early summer.


Easy to grow; part shade and good drainage seem to work well. After a few years, you’ll have several offsets to share with your dearest friends/worst enemies.

At the peak of bloom, the fragrance is reminiscent of lily or tuberose (if they were arranged on a patty of rotting hamburger).



Garden Interns Brittaney and Anna think it’s JUST FABULOUS!

Available from that purveyor of all plants phallic, 
Plant Delights.
(They have lots of other stuff, too.)

Ten years of life with the Green Menace: Part 2

Posted by Sara Tanis and Bert Cregg

NOTE: Last week I gave an update on the 10-year anniversary of the discovery of the emerald ash borer in the U.S.  In response to the post, Sonia John raised a couple of points:

“Please share your knowledge about the status of efforts to: 1. introduce insect species or other biocontrols that predate the EAB, and 2. evaluation of the degree of resistance to EAB of Asian (and European) Fraxinus spp. as well as Asian/N.American hybrids)” 

Sonia is right on the mark because these two areas of investigation probably represent the best long-term solution to the EAB issue.  As I mentioned last week, EAB was a relatively obscure insect in its native range in Asia, rarely causing any significant damage.  This suggests that native (Asian) ashes are resistant, native biocontrols keep it in check, or both.

In order to reply to Sonia’s post I enlisted the aid of Sara Tanis.  Sara is a Ph.D. student in the Department of Forestry at MSU (and a former MS student of mine) and is studying variation in susceptibility to EAB among ash species for her dissertation.

 

Biocontrols 
Almost from the moment that EAB was first identified, USDA and US university scientists have been working with their Asian counterparts to identify diseases or other insects that keep EAB under control in Asia.  From this work, researchers have identified several parasitic wasps that affect EAB.  Some of the wasps lay their eggs on EAB eggs – when the wasp larvae hatch they feed on the EAB eggs.  Other wasps lay eggs on the EAB larvae and then the wasp larvae feed on the EAB larvae – yeah, pretty gross.  (for more information visit http://www.emeraldashborer.info/biocontrol.cfm).  A state of the art bio-control research facility has been established by USDA-APHIS in Brighton, Michigan to rear these parasitoids and to date they have been released in several locations throughout infested areas of the United States.   We know the wasps are highly effective in parasitizing EAB eggs and larvae in China.  The question is whether we can establish viable and self-sustaining populations in the US.  

  

In addition, a native parasitoid Atanycolus cappaerti, a Braconid wasp described in 2009, is also proving to be successful in curbing EAB densities.  At the MSU Tree Research Center, we have seen more than 70% parasitism on EAB in black ash and green ash trees.  Hopefully turn-about with be fair play and lack of co-evolution will back-fire on EAB and our all-American native wasp can do a number it.  All together now: USA! USA! USA!

 

Everybody’s All-American? Atanycolus cappaerti  Photo: David Cappaert

Variation in resistance among species.

One of the main points to hit home here is the fact that even though Asian ash are considered “resistant” in their native habitat, in North America where EAB population densities are extremely high, they do succumb to EAB attack despite their co-evolutionary history.  Here at MSU, Andrea Anulewicz has done extensive host preference work using a variety of ash species including those found west of the Rockies (F. anomala), south in the Carolinas (F. caroliniana), Europe (F. excelsior and F. ornus), and an evergreen species found in Central America (F. uhdei).   All of these ash species have proven to be viable hosts for both adults and larvae.  However, EAB do prefer some ash species over others.  At the top of the menu are green ash and black ash, less preferred is white ash, and least preferred is blue ash, our hope for the future.   In the field, of the five ash species that EAB has encountered to date, blue ash appears to be the most resistant or the least preferred ash species native to North America.  In order to quantify differences in EAB related mortality between blue ash and white ash, we inventoried all living and dead trees in two woodlots in Southeast Michigan in 2010
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-2011.  We found approximately 68% (402 out of 590 trees) of the blue ash trees in these sites were alive, and most (60%) appeared healthy!  We calculated that these trees were subject to at least 178,000 beetles (calculated from dead ash phloem area) over the course of a 15+ year invasion.  That is a lot of beetles.  In contrast, only 29 of the 312 white ash trees survived, and these were likely too small to be infested during the peak of EAB invasion (around 2005).   Blue ash survival has also been reported in Ontario and Ohio.  Many of us assumed that there would be 99% ash tree mortality across North America.  Don’t get me wrong, many forests and urban areas DO have mortality this high because of the ash species found there.  However, we now have something positive to report.  Evidence suggests blue ash trees will persist in forests ravaged by EAB.  In addition, blue ash resistance might also enhance bio-control efforts.  The combination of a less susceptible host and a specialized parasitoid could maintain EAB populations at densities blue ash trees could sustain and possibly aid in slowing the spread of EAB across the US.  At this time, we don’t know the exact mechanism of blue ash resistance, but we are working on it.  Bert serves on my graduate advisory committee, so I’m sure he will keep you up to date as we learn more.  There are likely several factors that contribute, once isolated, we hope to incorporate these mechanisms into other ash species and introduce less susceptible ash tress back into the landscape. 


Variation in susceptibility to EAB between blue and white ash

USDA and Ohio State researchers are working with the Dawes arboretum to hybridize North American and Asian ashes.  This work is based on the model that the American Chestnut Foundation has used to breed blight-resistant chestnuts; starting with an Asian – American hybrid (1/2 Asian; ½ American) and then making repeated back-crosses with the American species to increase the desired horticultural characteristics while maintaining the resistance from the Asian parent.   Clearly this is a long-term proposition and so far the efforts have been slowed by poor crossibility among species and insect damage to seed.   Moreover, earlier hybrids that have been produced crossing Manchurian ash have not exhibited any resistant qualities.  Breeding work, of course, is always a numbers game.  As a point of comparison, the USDA National Arboretum’s program to select Dutch elm resistant American elms found only 11 survivors out of 21,000 seedlings screened for tolerance.

Pest Alert for western Washington – late blight

I know most of you are not residents of western Washington, but this information might be of interest to gardeners everywhere.

Pest: Late blight (Phytophthora infestans)

Hosts at risk: Tomato and potato

Conditions of risk: cool, moist environment

Found: Images typical of late blight infection on tomato have been submitted from two Puget Sound area (King/Snohomish county) farms.   Growing conditions were plants in field soil where the area was covered with a plastic hoop structure.

Potential impact: Significant crop losses may occur if not managed properly.

What action should be taken: Scout for evidence of the pathogen on the foliage, stems of tomato or potato, as well as the fruits of tomato. Look for black discoloration to the foliage and a halo of sporulation around the edge of the damage if conditions are moist. Keep the foliage as dry as possible. Maintain good air circulation around plants. A variety of preventative fungicides (both organic and conventional options) is available – click on the links above for tomato and potato.

Information is also available on the PNW Plant Disease Management Handbook website.

This Really Bugs Me

I get things wrong sometimes – I’ve had slip ups when speaking and said things I didn’t intend to say.  I’ve written things that I wish I had the chance to rewrite because I explained things poorly.  I’ve even gotten my facts mixed up from time to time.   Still, it bothers me when someone who should know better delivers information that is blatantly wrong.

Yesterday I was looking at YouTube videos regarding compost tea.  As anyone who has ever looked up compost tea on YouTube knows, if you look long enough you’ll eventually come to videos of Dr. Elaine Ingham.  She’s one of the biggest proponents of compost tea out there and is also Chief Scientist at the Rodale Institute.   Here’s a link to one of the videos that I ended up watching.  Interestingly, it doesn’t have much to do with compost tea.

http://www.youtube.com/watch?v=GEtl09VZiSU

To be fair, she makes some excellent points in the video about people needing to conserve the life in soil.  And I did like her basic definition of soil and dirt at the beginning.

Other points aren’t as well made.  As I was viewing this video I heard something that really ticked me off.

Go to 9:20 on the video and watch for a couple of minutes.  Listen to the insights about wartime munitions.

Then forget what you heard because it’s all just wrong.

Look, I know Dr. Ingham is a proponent of organic foods and techniques, but, if you’re going to talk about history, especially if it’s the history of a practice you’re opposed to, then you should really try to get it right.

She starts by talking about leftover munitions from World War Two and how we found that they could be put into farmers’ fields to kill weeds.

Wrong.

It’s true that one of our most used herbicides, 2,4 D, came from World War Two – but it wasn’t a munition (at least not in the classic sense of the word), and it wasn’t actually used in the war to any great extent.  It was released for use by farmers after the war was over.  And it sure wasn’t an explosive (otherwise there’d be lots of lawns in suburbia reduced to craters!)

Then she discusses using TNT as a fertilizer.  Was she joking?  If so that’s fine, but it didn’t seem like she was joking to me.

To be clear, while I’m sure somebody somewhere dumped TNT on their fields to see if it would work as a fertilizer, dumping munitions on fields to get plants to grow was in no way a common practice at any time.  In fact, a challenge for ecologists is getting rid of old munitions in contaminated sites (like old factories that made bullets and shells).

And then she says that synthetic nitrogen is Second World War technology, and that it’s the reason the Allies won.

Wrong.

Synthetic nitrogen is First World War technology and the Germans came up with it.  Haber and Bosch, the two guys who worked it out, both won Nobel Prizes for it.  (As a side note Haber was known as the father of chemical warfare for his WWI exploits with chlorine and other poisonous gasses).

Look, it’s not the end of the world if Dr. Ingham didn’t know this stuff, but my goodness, if you don’t know something mightn’t it be wise to avoid the topic?  If anyone is interested, the best books on synthetic nitrogen are Vacliv Smil’s Enriching the Earth and Thomas Hager’s The Alchemy of Air.

There were other problems on the video too.   For example, her bird guano comment didn’t really make sense since by World War Two it wasn’t economically realistic to use it any more –the guano, mined in Peru, had been largely used up – it’s not a quickly renewable source of fertilizer.  And the rain forest analogy she used is a terrible one because a rain forest is a relatively closed system containing organisms highly specialized for living in that environment while food production systems aren’t closed systems (and can’t be unless we reuse our own waste for fertilizer).  But I’ll leave those alone.  They were more irritating than infuriating.

Unfortunately Dr. Ingham has a little bit of a history with getting accurate information out.  I won’t go into it, but you can read the following if you’re interested:

http://www.biotech-info.net/green_lobby.html

www.biotech-info.net/ingham_rebuttal.pdf

I believe that the Rodale Institute is a quality institution, that its goals are honorable, and that organic techniques need to be given more consideration and implemented more frequently than they currently are in our country and the world.  That said, I question how seriously the good work that Rodale does will be taken with Dr. Ingham as its Chief Scientist if she continues to deliver information of the quality seen in this video.

Why I don’t like cardboard mulch

I’ve discussed my dislike of cardboard mulch before: like other sheet mulches it restricts water and gas transfer between the soil and atmosphere. In published comparison studies, other mulch choices generally outperform cardboard in terms of plant growth, weed control, etc. But there’s one area where cardboard is tops compared to every other mulch material tested.

Termites.

 

Termites LOVE cardboard. Did you know that termite researchers use cardboard feeding stations to lure termites? And cardboard is often used as the “control” in feeding studies, because termites will always eat it?

People seem to think that wood chips are termite magnets. Though termites can eat some types of wood, they prefer cardboard in taste testing. If they are given no choice and have only wood to eat, they will consume it but their survival rate decreases. Dead termites don’t reproduce.

To give termites a bit of a break, they are very useful in bringing life back to crusted, arid soils: studies have shown that just adding mulch and termites to these degraded soils is enough get biological processes going again.

But personally, I’m not providing a cardboard welcome mat for termites to the gardens surrounding my wooden house.  Hopefully you won’t either.

Ten years of life with the Green Menace

This summer marks an anniversary of sorts.  Shortly after I joined the faculty at Michigan State University in the fall of 1999 MSU Extension began to get reports of dead and declining ash trees in and around Detroit.  Since ash trees had relatively few serious pest issues and none that routinely caused mortality, the mysterious ash decline was attributed to cumulative environmental stresses, ash yellows or various site factors.  In the summer of 2002, however, a little-known exotic beetle from Asia, emerald ash borer (Agrilis planipennis) was identified as the causal organism.  The beetle was so obscure that the first insects collected had to be sent to an entomologist in Eastern Europe for identification.  The summer of 2002 has become a point demarcation for those that work in landscape horticulture or urban forestry in the Midwest and East; now it’s before EAB and after EAB.  Prior to 2002,  EAB was completely unknown in the US, today it has been identified in 15 states and 2 Canadian provinces.  Barring a dramatic turn of events EAB may essentially destroy the entire Fraxinus genus in North America. 

EAB range June 2012

In the intervening 10 years we have learned a lot about the beetle.  In fact, it seems likely that we have learned more about EAB in 10 years than just about any tree pest in history.  I did a quick Google Scholar search and there have been nearly 600 articles published with ‘emerald ash borer’ in the title since 2002. Below are some highlights of what we’ve learned.

Life cycle.  In lower Michigan, EAB is able to complete its life cycle in one year.  Adults emerge in early summer, feed on ash tree foliage, mate, and lay eggs on ash tree bark.  When the eggs hatch the larvae burrow into the tree and feed on phloem under the bark leaving extensive galleries.  The larvae eventually pupate and overwinter before emerging as adults the next summer, leaving a characteristic D-shaped exit hole.

EAB life cycle – National Plant Gemplasm System

Host range.  When EAB was first discovered very little was known about the insect, even in its native range in China and Korea.  At the time, information from its native populations suggested that EAB could affect trees outside the genus Fraxinus.  Research in the US, however, has clearly demonstrated that EAB adults can only feed on Fraxinus foliage and EAB larvae can only develop by feeding on ash tree phloem.  So there is little likelihood that EAB will ‘make the jump’ to other tree species outside of Fraxinus.  That’s the good news.  The bad news is that all North American ashes are susceptible to EAB.  There are some differences in relative susceptibility; green ash trees are probably the most susceptible, while blue ash trees will hang in there the longest. Eventually, though, all North America ashes will succumb.

How not to stop an exotic invasion.  While much of what we’ve learned about EAB has been through systematic research, we have also learned by trial and error.  Immediately after EAB’s discovery regulators decided the best approach was try to eradicate the pest.  Historically eradication efforts have not been very successful but decision-makers at the time may have been buoyed by the recent successful eradication of Asian long-horned beetle in the Chicago area.  To make a long story short, EAB eradication failed.  In 2002 the EAB infestation was made up of a core population in and around Detroit and a series of isolated outlier populations.  The eradication strategy was analogous to fighting a forest fire – build a perimeter around the main hot spot and eliminate outlying ‘spot fires’ as soon as they appear.  With EAB the fire fighting analogy broke down for two reasons.  First, it was impossible to contain the main population since the insect was continually carried out of the core area, largely by campers moving firewood (It’s a Michigan thing).  Secondly, fire-fighters can rapidly respond to isolated spot fires because smoke identifies the location almost immediately. With EAB there is typically a 2-3 year lag period once the beetle moves into an area until trees begin to show symptoms.  By that time the population is well established and has likely already spread beyond any potential containment. 

Saving your ash. In 2002 there was no data on effectiveness of insecticides against EAB.  Therefore researchers and extensions specialists, did not provide recommendations for arborists to control it.  Several arborists ignored our advice and treated tre
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es in the core infestation areas in Detroit with insecticides.  In some cases those trees are still alive.  So were the arborists right and were we wrong?  I think both groups did what they had to do.  As scientists and extension specialists we can’t make recommendations in the absence of data.  In many cases the arborists took a ‘sledgehammer’ approach, using multiple products and multiple applications. They saved some trees but they probably used more chemical than they needed to and probably hit some beneficial and other non-target insects along the way.  Today, with the benefit of nearly decade of research, we have effective controls for individual trees, primarily using trunk-injected systemic insecticides.

http://www.emeraldashborer.info/files/Multistate_EAB_Insecticide_Fact_Sheet.pdf

What’s next.  The range of EAB continues to expand.  While it is possible to protect individual trees, we need to remember those trees will require treatment in perpetuity to survive.   The development of hybrid ashes – similar to what has been done with elms – seems like to most likely scenario that will get ashes back into the landscape.  In the meantime, EAB joins chestnut trees and elms as another reminder of the need to diversify our landscape in order to reduce risks associated with exotic pests.

A Tale of Two Herbicides

I performed a little demonstration the last few weeks which I thought you might be interested in seeing.   So here it is:

I took a little weedy spot of land out in the nursery and divided it into four sections.  Three weeks ago I applied Round-up to one of the sections and vinegar to another.  Then, a few days ago, I applied vinegar (again) to the third section and Round-up (again) to the fourth.  Then yesterday I took pictures of all four sections.  I conducted this little experiment so that I could demonstrate to a group what happens over time after you apply these chemicals.  The results are below.

Above is the Round-up treatment a week or so after application.

And here’s the Round-up after three weeks.

The Vinegar after a few days.

And the vinegar after three weeks.

Vinegar is great for little weeds, but boy oh boy, once they grow up, vinegar just doesn’t do it.

Of Football and Forests

 Howdy all – I’ve been on vacation and then inundated by all that accumulates whilst on said holiday. Here’s a whopper of a belated post. What follows is an account of events you may find interesting (or amusing, or frustrating).

Here’s a portion of a recent press release from the media office at Virginia Tech, regarding our making the "Green Honor Roll."

BLACKSBURG, Va., April 25, 2012 – For the third consecutive year, Virginia Tech ranks among the most environmentally responsible colleges in the United States and Canada, according to the Princeton Review, receiving the highest possible score given by the organization.

The Princeton Review’s Guide to 322 Green Colleges: 2012 Edition, released April 17, profiles institutions of higher education that demonstrate a notable commitment to sustainability in their academic offerings, campus infrastructure, activities, and career preparation. The Princeton Review, in collaboration with the Center for Green Schools at the U.S. Green Building Council, evaluates colleges and universities and assigns a numerical score on a scale of 60 to 99. 

Virginia Tech received a score of 99, earning the distinction as one of 16 colleges to be named to the Princeton Review’s 2012 Green Rating Honor Roll

“Virginia Tech continues to be totally committed to campus sustainability," said Denny Cochrane, Virginia Tech’s sustainability program manager. "Our inclusion on the Green Rating Honor Roll shows how wide spread the commitment is among out students, faculty, staff, alumni, and university leadership."

********

The story of “Stadium Woods” is interesting and complex.  Virginia Tech Athletics announced the construction of an indoor practice facility for football on part of an 11-acre wooded site, behind Lane Stadium and abutting the current practice field (hence “stadium woods”).  The campus Landscape Architect brought it up at a meeting with the campus Arboretum Committee, who were not thrilled. Virginia Tech has followed a plan of very concentrated/intense land use to keep everything within walking/running distance for the students, and this was one of the few wooded areas left.

The committee proposed an alternative site a few hundred yards away, with the new facility replacing some tennis courts and a roller-hockey rink. 

This suggestion was not met with great enthusiasm by the Athletics department.

Two possible sites for indoor practice facility, adjacent to practice field where 200-300 year old trees are, or along Washington Street on top of some tennis courts (also possibly 200 years old).

At that point, an immense hoo-ha began that would stretch over a year.  I’m going to leave out the ensuing committee/administrator/athletics blow-by-blow, but in a nutshell, some of the Forestry faculty determined this was not just “woods” but a rare stand of old-growth forest, and the Athletics folks were insistent “this is absolutely the best place for the facility!”   Football is huge at Virginia Tech, thus anything described as giving an edge in recruiting gets maximum priority.  In the event of a thunderstorm, having the student-athletes run an additional 150 yards from the practice field to the alternative indoor facility location was just not acceptable. Other issues included digging up a ton of infrastructure (steam lines, electric, etc.) that runs along the road, plus the height of the proposed building does not conform to the campus Master Plan (since it’s for football, it has to be be tall enough to kick a field goal in. We really do need a lot of practice at that.) Guesstimates are around $1million increase to account for the infrastructure issue (added to the $15 million estimate for construction).

A community group “Save Stadium Woods” was formed, complete with a (very nice) website and a letter-writing campaign to the local newspaper. There were petitions, resolutions from everybody and their mother, and more.  The local coverage was intense plus there was a letter to the editor in nearly every newspaper issue for the past three months. CNN even covered the story, which was great, as no campus shootings were involved for the first time in a
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while.  One of the 300+ year old white oaks was named “Stephen Colbert” in an effort to raise awareness (?!?).  

An ad-hoc committee of university administrators, both Athletics and non-, plus interested parties from both the faculty and the community was charged by the President to come up with a solution. 

And of course, a third-party consultant was brought in, because we apparently don’t have enough smart people here on campus.

Yes, quite the head-scratcher… place the building and site footprint on top of 3 acres of steeply-sloped, old-growth forest? Or remove some aging and underused tennis courts, which could be relocated to the intramural athletics area on the fringe of campus. Yet Athletics continued to argue, and University administration was silent.

The committee weighed in a week ago, coming to the logical conclusion of protecting the woods and utilizing the tennis court site.  I guess the weirdest part of this is that something so no-brainer-ish was allowed to drag on and on, giving our beloved Virginia Tech and so-called “Green University” (complete with TreeCampus USA designation) a black eye. 
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